Sometime before the events of the books, Festus was created and activated inside Bunker 9 by the Hephaestus campers and a blessing from the fire god. A set of wings was revealed inside the bunker in The Lost Hero; it's unknown whether they were originally for the dragon and, if they were, why they were never put on him. Also, before his creation, a set of blueprints was made for a Greek trireme lit by flames, and Festus' head was planted in the bow of the ship.

Festus was created to defend the camp from monsters before Thalia Grace was turned into a tree by her father to save her life. However, about fifteen years before Percy's arrival at camp, he malfunctioned and ran off into the woods, where he eventually broke down. His body was somehow buried in the ground and he was lost for a long time.